The purpose of this contract is to supply materials from cancer patients and family members for SVCP investigators in virological, immunological, and biochemical laboratories. The present contract provides for the supply of serum samples collected from leukemia patients and their family members, matched hematological controls, and pediatric patients without evidence of malignancy. In the forthcoming year, emphasis will shift to the furnishing of solid-tumor material particularly from patients with Wilms tumor, neuroblastoma, lymphomas, brain tumors, and osteogenic sarcomas.